Performance Check— Type 1A1
4. Check Alternate Mode Operation
a. Requirement— Proper alternation of channels and trace
slaving to the Type 547 Oscilloscope time bases.
b. Set the MODE switch to ALT, then position Channel
1 trace 1 cm above the graticule centerline, and Channel 2
trace
1
cm below the graticule centerline by means of the
POSITION controls.
c. CHECK—The sequence of alternation one step at a
time for all settings of the Time Base B Time/Cm switch.
(The Intensity control for the test oscilloscope will have to
be adjusted as the sweep rate is changed, brighter for the
faster sweep rates and reduced for the slow rates.)
d. Set the Time Base Time/Cm switch to 10/xs.
NOTE
Perform the remainder of Step 4 only if the Type
1A1 is used in conjunction with an oscilloscope
which has provisions for alternate slave opera
tion (e.g.. Type 5 4 7 ).
e. Requirement— Two trace display. Channel 1 slaved to
Time Base A and Channel 2 slaved to Time Base B.
f. Set the Type 547 oscilloscope controls as follows:
Time Base controls
A Time/Cm
.5 mSEC
B Time/Cm
10/xSec
A Triggering controls
Set the same as B Triggering controls.
Other controls
Horizontal Display
A/ALT/B
Intensity
Both traces visible
NOTE
With the Time Base controls set as above, the dim
mer trace identifies Time Base B due to its faster
sweep rate setting.
g. CHECK— Rotate the Channel 1 POSITION control. This
should change the position of Time Base A trace. Rotate the
Channel 2 POSITION control. This should change the posi
tion of Time Base B trace.
h. Set the Time Base B Time/Cm switch to .1 Sec and
check for alternate trace.
i. Set Time Base B Time/Cm switch to .5 /xSec and the
Horizontal Display switch to B.
Type 1A1
MODE
CHOP
Type 547 Oscilloscope
Triggering Level
Near 0 and knob
pushed in
Time/Cm
.5/xSec
Horizontal Display
B
c. Using the Type 1A1 POSITION controls, position Chan
nel
1
segmented trace about
1 .0
cm above graticule center.
Position the trace for the other channel about 1.0 cm below
the graticule center. Use the oscilloscope Triggering Level
control to obtain a stable display (See Fig. 6-1 A).
d. CHECK—That the display is set for normal viewing
intensity. Set the oscilloscope CRT Cathode Selector switch
to the Chopped Blanking position.
e. Switch transients between channels should be blanked
out (see Fig. 6-1B).
Bid
c
nked Out
-
-
/
„|rt
; Swc ep R ite: C.5
/is
'cm
(A )
0 .8 3 3 /£$
to
r
1.2 5 /is
------- 1
1
-------
,___ „
L - _
>— .
|—
SW€ ep R<ite: C.5
i i s j
cm
(B)
Fig. 6 -1 . (A ) Blanked chopped-mode waveform; and (B) unblanked
chopped-mode waveform.
5. Check Chopped Mode Blanking
a. Requirement— Blanking of between-channel switching
transients.
b. Set controls as follows:
f.
Change the Time Base B Time/Cm switch to .2 /xs and
check the waveform distortion. It must have a flat top
with no more than 2 mm of slope. (Disregard wrinkles that
may be on the flat top.) Return the CRT Cathode Selector
switch to CRT Cathode position and the Time Base B Time/
Cm switch to .5 /xs.
6-3
